https://devzone.nordicsemi.com/f/nordic-q-a/11367/is-the-word-host-in-bt-core-spec-same-as-vol-3-host-volumeHi,all, in the Core 4.2, the sentence with word &#39;Controller&#39; and &#39;Host&#39; have appeared many times. like &#39;When a Host performs the auto connection establishment procedure, the Host configures the Controller as follows: &#39; i think the controlleren-USTelligent Community 13Mon, 01 Feb 2016 07:44:01 GMThttps://devzone.nordicsemi.com/thread/42834?ContentTypeID=1Mon, 01 Feb 2016 07:44:01 GMT137ad170-7792-4731-bb38-c0d22fbe4515:95ea91d8-12d7-45c5-87fd-f6b726fcb2f7Susheel Nuguru<p>Sorry for the late reply.</p> <p>from the spec.</p> <blockquote> <p>The Bluetooth core system consists of a Host and one or more Controllers. A Host is a logical entity defined as all of the layers below the non-core profiles and above the Host Controller Interface (HCI).</p> </blockquote> <p>This means that the HOST should contain ATT, ATTDB, GATTC, GATTS, UUID, SMP, L2CAP and GAP</p><div style="clear:both;"></div>